package com.sfac.javaSpringBoot.interceptor;

import org.apache.commons.lang3.StringUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.stereotype.Component;
import org.springframework.ui.ModelMap;
import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

/**
 * @Description ViewMappingInterceptor
 * - 自动封装 template 路劲
 * - 约定：目标页面的相对路劲地址与 path 路径保持一致
 * @Author HymanHu
 * @Date 2021/8/23 13:26
 */
@Component
public class ViewMappingInterceptor implements HandlerInterceptor {

    private final static Logger LOGGER = LoggerFactory
            .getLogger(ViewMappingInterceptor.class);

    @Override
    public boolean preHandle(HttpServletRequest request,
                             HttpServletResponse response,
                             Object handler) throws Exception {
        LOGGER.debug("==== ViewMappingInterceptor Pre Handle ====");
        return true;
    }

    @Override
    public void postHandle(HttpServletRequest request,
                           HttpServletResponse response,
                           Object handler,
                           ModelAndView modelAndView) throws Exception {
        LOGGER.debug("==== ViewMappingInterceptor Post Handle ====");

        // 判断请求是否返回 view，如果是 rest 接口 || redirect || forward，则不作处理
        if (modelAndView == null ||
                modelAndView.getViewName().startsWith("redirect") ||
                modelAndView.getViewName().startsWith("forward")) {
            return;
        }

        // 从请求中得到 path
        String path = request.getServletPath();
        // 判断 modelMap 中是否有设置 template，如果已有，则无需设置
        String template = (String) modelAndView.getModelMap().get("template");
        if (StringUtils.isBlank(template)) {
            // 在 modelMap 中设置 template，值为 path
            path = path.startsWith("/") ? path.substring(1) : path;
            modelAndView.getModelMap().addAttribute("template", path);
        }
    }

    @Override
    public void afterCompletion(HttpServletRequest request,
                                HttpServletResponse response,
                                Object handler,
                                Exception ex) throws Exception {
        LOGGER.debug("==== ViewMappingInterceptor After Handle ====");
    }
}
